Induction heat-treating apparatus



Aug. 8, 1950 H. A. STRICKLAND, JR

INDUCTION HEAT 'IREATING APPARATUS 3 Sheets-Sheet 1 Filed March 22, 1947 Hcuold Q. Stridzlandk W a. Gtu-uQJ ATTORNEY Aug. 8, 1950 H. A. STRICKLAND, JR

Ne APPARATUS INDUCTION HEAT TREATI Filed March 22, 1947 3 Sheets-Sheet 2 8- 1950 H. A. STRICKLAND, JR 2,517,607

INDUCTION HEAT TREATING APPARATUS Filed March 22, 1947 s Sheets-Shet s INVENTOR Harold 4%. gtricmandjr. BY ma aww ATTORNEY Patented Aug. 8, 1950 UNITED STATES PATENT OFFICE INDUCTIDN HEAT-TREATING APPARATUS Ohio Application March 22, 1947, Serial No. 736,439

3 Claims.

This invention relates to heat treating apparatus, particularly to apparatus for heating and quenching two circumferential surfaces of a workpiece and more particularly to apparatus for heat treating short workpiece having an external groove, and has for an object the provision of improvements in this art.

One of the particular objects of the invention is to provide means for accurately placing the workpiece relative to the heating means and for furnishing an indication whether the workpiece is of proper length.

Another object is to provide improved means for heating the external groove of a workpiece.

Another object of the invention is the provision of a new and improved inductor comprised of segments each. adapted to be moved into and out of mating engagement with a recess on the surface of a workpiece, the ends of the segments being cut away so as to facilitate movement of the workpiece in a direction transverse to the plane of the segment.

Another object is to provide improved means for enabling, introducin and removing a workpiece into and from an induction-heating coil.

The above objects and certain novel features will be apparent from the following description of an exemplary embodiment, reference being made to the accompanying drawings thereof,

wherein:

- Figure 1 is a front elevation of the apparatus; Figure 2 is an enlarged horizontal section taken on the line 22 of Fig. 1;

Figure 3 is a vertical section taken on the line 3-3 of Fig. 2 but with the workpiece in heating position;

Figure 4 is a partial section similar to Fig. 3 but showing the workpiece in quenching position;

Figure 5 is a horizontal section taken on the line 5-5 of Fig. 4; and

Figure 6 is an axial section through the hardened workpiece, showing in dotted lines the relation thereto of the heating means.

, The apparatus in general comprises a support for holding a relatively short workpiece such as a sheave which is to be hardened on the interior of the hub and within the external groove, means for moving the workpiece support into heating and quenching position, means for moving the external heating means laterally into and out of heating position, means for moving the external quenching means axially to clear the workpiece position for the introduction and removal of a workpiece, and means for accurately gauging the thickness and position of the workpiece in heating position to prevent the application of heatin current until the proper arrangement is attained.

The apparatus illustrated in the drawings includes fixed frame it] to which a plurality (two here) of spaced parallel guide rods l2 are secured at their ends by clamps i3, the rods 12 being spaced outwardly from the vertical portion of the frame it and each being provided intermediate its ends with a piston i4. Suitable ports and passages in the rods provide for the flow of motive fluid to and from the cylinders. Operatively associated with each piston M, which is mounted thus in a fixed position, is a cylinder it, and these cylinders are rigidly connected by a cross piece ll. The connected cylinder assembly may be referred to as a carriage.

Upon the carriage on bearings I8 and [9 there is rotatably mounted a tubular workpiece support 2%. The support is rotated through gears 13! and 22 by a motor M mounted on the carriage. At its upper end the support 20 carries a' workpiece holder plate .23 having an interior opening adapted to receive and accurately position the flanged hub of the workpiece W and a reduced outer edge adapted to receive the outer edge of the workpiece.

The intermediate portion of the tubular workpiece support Zt is provided with a plurality of holes 25 for the passage of quenching fluid to the interior, and a depending tubular extension 2'! telescoped within an upstanding fixed drain tube 28 emptyin into a pipe 29 (Fig. 1). The transverse web 32 and upstanding sidewalls 33 of the carriage constitute a collecting basin for quench fluid, and a depending pipe 34 therefrom cooperates with a telescoping pipe 35 and the drain pipe 29 to remove fluid from this basin. As shown in Fig. 6, the workpiece is hardened at W! on its inner circumference, as by a heating head 38 shown in dotted lines, and at W2 on its outer grooved circumference, as by a heating head 39 also shown here in dotted lines. The heating means will be discussed in detail hereinafter. It will be understood from the fact that the workpiece is hardened by induction heating and quenching, that it is composed of a metal which is of such a nature that it is sub- .iect to being heated by induction heating means (usually high frequency) and to being quenched by a fluid such as air, water, oil or other known medium, the workpiece being of the same chemical composition throughout before and after hardening as distinguished from a metal whose chemical character is changed by the hardening process.

The means for quenchin are shown in operative relationship to the workpiece in Fig. 4, a fixed quench tube 40 being secured within the tubular support 20 and drain pipe 28, with its perforated end or head M properly located to quench the interior hub surface WI when the workpiece is in its lowermost position, and a quench head 42 being supported on depending rods 43 which are movable (with pistons, not shown) within fixed cylinders M, the quench head having its perforated inner portion 55 properly located to quench the exterior sheave groove W2 when the workpiece is in its lowermost position and the quench head is in its uppermost position.

Quench fluid is supplied to the quench tube ill by a pipe 48, and to the quench head d2 by pipes 49 connected to flexible hose, not shown. Motive fluid is supplied to and removed from the cylinders 44 by pipes 50. When the quench head is moved down to its lowermost position the upper end of the workpiece support and the plate 23 are exposed above the quench head to permit easy insertion and removal of a workpiece.

The hub heating head 38 is supported in fixed position upon a tubular rod 52 supported at 53 on the frame iii and supplied with electric current, coil cooling fluid, appropriate insulation, and the like in known manner.

Means are provided for accurately locating and gauging the workpiece in heating position and these means are coordinated with means for clamping the workpiece for rotation. As shown in Fig. 3, a tubular workpiece clamp 55 engages the upper end of the hub of the workpiece when it is in its uppermost position. The clamp mem ber 55 is carried adjustably by a rotatable head member 58, a locknut being provided for ho1ding the parts securely in adjusted position.

The head member 56 is, through bearings 58, rotatably mounted on a sleeve 59 which is vertically slidable on a fixed tubular support 68. A coil spring 6! urges the sleeve 59 downwardly. Secured to the sleeve 59 in spaced relation, as by stud bolts Ed, is an annular plate 55 adapted to operate switches SI and S2 which are mounted on the fixed support 60. The sleeve 59 may be pro vided with an outstanding flange 66 to furnish convenient anchorage for the bolts 64. The bolts have nuts or heads at their upper ends to prevent the sleeve 59' from moving too far downwardly by the action of the spring GI and gravity.

A convenient way to mount the fixed support 60 is to make it as a split part and clamp it to the fixed induction head supporting rod or mandrel 52, as by bolts 61'.

Cable 58, 69 connect the switches Si, S2 into a power control circuit of any suitable type. The switches may be either of the make or break type but it is not thought to be necessary to illustrate either the switch or circuit details, these being matters regularly supplied according to requirements.

When the workpiece is of the proper thickness at the hub and is pushed up accurately into heating position, as shown in Fig. 3, one of the switches, as SI, will be cleared from the operating plate 65 while the other will not be cleared. In this situation the circuit is cleared for operation; but if neither switch is cleared or if both are cleared the machine will not operate to heat the workpiece. The switches are of the micro type so that the movements involved are very small.

The induction heating head 38 for heating the bore WI of the workpiece has already been described and the external heating head 39 has been referred to. As shown in Fig. 5, the head 39 is made in two semicircular parts 39a and 391) which can be moved radially toward and from each other to embrace the workpiece for heating or to clear it so it can be moved axially into and out of heating position. The parts 39a, 3% are cut away adjacent their meeting edges, as at 12, to clear the outer edge of the workpiece.

The induction heating head 39 is made as a single turn coil which is supplied with current by conductors l3 and M which are adequately flexible in keeping with their length to accommodate the movements of the parts of the head toward and from each other. At the other side, the front, the parts 39a, 3% are connected by a flexible jumper conductor it. The conductors '53, i i and it, to have suitable flexibility, may be formed of laminated soft copper strips.

Cooling fluid is supplied to and removed from the heating head 39 by flexible conduits I7 and is transferred between the divided head parts by a short flexible jumper conduit it.

Means are provided for moving the heating head parts 35a, 3% toward and from each other. As best shown in Fig. 5, the parts 39a, 39?) are mounted on insulating blocks 89, which blocks, as shown in Figs. 2 and a, are secured to the parts by bolts 8 l.

The blocks 88 have secured thereto, as by pins 82, operating rods 83 which operate in guide passages in brackets E i and the rods 83 areconnected in pairs beyond the brackets by crossbars 85. Piston rods 86, operated by pistons within cylinders tl, are secured to the crossbars 85 intermediate their length. The inward position of the crossbars 85 and or" the heating head parts 35a, 3% carried thereby is defined and limited by stop screws 98 provided with locknuts 9|. Motive fluid is supplied to and exhausted from the cylinders Bl by conduits 92.

As shown in Fig. 3, the brackets 8 are secured to the base frame 26 by bolts 93 and provide openings between the rods 83 for accommodating the large carriage cylinders H5. The brackets also provide suitable portions 85a at their inner ends which form guides for the quench head operating rods 33 and mounting means for the cylinders 44.

In operation, a workpiece W is introduced when the quench head 52 and the carrier plate 23 are in their lowermost positions. As shown in Fig. 1, the workpiece position is accessible from the front between the rods 33 and above the quench head 42 carried thereby at this time.

The carriage, comprised of the cylinders l6 and the cross member ii, is then moved upwardly as shown in Fig. 3, the heating head parts 39a, 391') being in their separated position at this time, until the switch S! is cleared but without clearing switch S2. The ends of the cylinders [6 at this time abut the ends of the pistons It to limit upward movement. The switches SE, S2 register the completion of this upward movement and determine whether the workpiece is too thick or too thin. If conditions are not right the machine does not heat the workpiece.

With the workpiece in correct heating posi tion, the exterior heating head elements 39a, 3% are forced inward by their rods 83 and connected motive means until the crossbars 85 engage the heads of the limit gauge bolts 90. The contoured inner surfaces of the heating head parts 39a, 3911 then fit accurately within the groove W2 of the workpiece, as shown in Figs. 3 and 6. The internal heating head 38 being fixed in position is also suitably disposed with relation to the internal surface W! of the workpiece.

' If sufficient power is available both heating heads 38 and 39 may be operated simultaneously but when desired they may be operated in succession, preferably the inner first and the outer following.

After the workpiece has been heated it is moved down to the quenching position shown in Fig. 4, the heating head parts 39a, 39b first being moved apart to clear the grooved outer edge of the workpiece as it moves down. The quench head 42 is moved up into quenching position and when the parts are all in proper position fluid is supplied to the inner quench head 4! and to the outer quench head 42 simultaneously, toquench both the inside surfaces W5 and W2.

After quenching, the quench head 42 is moved back down to the Fig. 1 position to permit the hardened workpiece to be removed and a new workpiece to be introduced.

While the invention has been described as applied to treating an externally grooved workpiece it will be understood that it is applicable to any workpiece which has any portion extending outwardly beyond the surface to be treated so as to make useful the radially movable heating head parts; and in certain aspects the invention is applicable, of course, to workpieces having uniform and readily accessible outer surfaces.

While one embodiment of the invention has been described in detail, it is to be understood that there may be various embodiments within the limits of the prior art and the scope of the subjoined claims.

What is claimed is:

1. Apparatus for heat treating an article, com prising in combination, an axially movable workpiece support, electric induction heating means for heating the workpiece externally at one point along its axis of travel, said heating means including divided parts mounted to move radially toward and from the axis of the workpiece and having elements adapted to be positioned radially within a radially projecting element of the workpiece, said divided heating head parts being radially cut away adjacent their meetin edges to provide clearance when in their radially retracted position for the radially projecting part of the workpiece during relative axial movements.

2. Apparatus for heat treating an article, comprising in combination, a workpiece support, an induction heating head adapted to induce heating currents in a radial recessed portion of the workpiece, said workpiece support and heating head having axial movement relative to each other, said heating head being divided and the parts thereof having radial movement relative to the axis of the workpiece and heating head, and said heating head parts being cut away radially near their meeting edges to provide clearance for radially extending portions of the workpiece during the relative axial movements.

3. Apparatus for heat treating an article, comprising in combination, an axially movable workpiece carriage, an axially movable quench head adapted to surroundingly embrace the workpiece, laterally spaced axially movable power means for moving said workpiece carriage, fixed brackets surrounding said power means, a heating head having radially movable parts, operating rods for said heating head parts and reciprocable generally laterally to said workpiece axis, said rods being mounted in said brackets and spaced on opposite sides of said power means, and operating rods for said quench head mounted for movement on said brackets.

HAROLD A. STRICKLAND, JR.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,255,103 Denneen et a1 Sept. 9, 1941 2,277,564 Somes Mar. 24, 1942 2,280,064 Denneen et al Apr. 21, 1942 2,308,788 Somes Jan. 19, 1943 2,368,809 Denneen et al Feb. 6, 1945 2,399,896 Somes May 7, 1946 2,408,229 Roberds Sept. 24, 1946 2,456,091 Stevens et a1 Dec. 14, 1948 2,464,727 Storm Mar. 15, 1949 OTHER REFERENCES Curtis: How to Design Coils for Induction Heating, American Machinist, January 31, 1946, pages -78. 

